Touch screen devices allow a user to control the device by physically touching images presented on the device. For example, a virtual button displayed by the device can be physically touched on the device as a way of actuating the virtual button. Until recently, such touch screen devices have only been able to recognize one touch input at a time. However, advances in touch screen technology have allowed multiple touches to be concurrently recognized. With the development of multi-touch, touch screen devices, powerful multi-touch input modalities are being established. In particular, many multi-touch gestures have been created that are believed to increase user enjoyment and productivity.